A Brazilian mechanic has found a cheap and innovative way to produce light that is up to 40 or 60 watts - with just a plastic bottle, water and bleach.
The 'Moser lamp' developed by Alfredo Moser has taken off in the Philippines, where a quarter of the population lives below the poverty line, and electricity is unusually expensive, with the lamps now fitted in 140,000 homes.
Moser's cheap and environmentally friendly invention is picking up steam in other developing nations around the world.
"It's a divine light," Moser told the BBC.
"God gave the Sun to everyone, and light is for everyone. Whoever wants it saves money. You can't get an electric shock from it, and it doesn't cost a penny," the inventor said.
Moser harnesses solar power by refracting sunlight through a clear two-litre plastic bottle that is filled with water.
"Add two capfuls of bleach to protect the water so it doesn't turn green (with algae). The cleaner the bottle, the better," he said.
Moser then tops the bottle with a black cap, pushing it through a hole in his roof.
"You fix the bottle in with polyester resin. Even when it rains, the roof never leaks - not one drop," Moser said.
In many parts of the developing world, millions of families still drill tiny windows into their shacks to let a little bit of light peek in, the report said.
The idea for the lamp came to Moser in 2002, during one of the blackouts in his hometown, Uberaba, Brazil. He needed a unique way to light his workshop.
Once he figured out the magic recipe, he placed the lamps in his neighbour's homes and his town's supermarket.
